Field of the Invention
The present disclosure relates to an image display device and driving method thereof.
Discussion of the Related Art
With rising interests in information displays and increasing demands to use portable information media, researches and commercialization of light-weight and thin-profile image displays have been actively carried out. Examples of the image displays include a liquid crystal display (LCD), an organic light emitting diode (OLED), a field emission display (FED), etc.
Among these image displays, the liquid crystal display displays moving pictures using a thin film transistor as a switching element. Liquid crystal display can be made smaller in size than cathode ray tubes and is used extensively in a personal computer, a laptop computer, and a portable device such as office automation equipment or a mobile phone. Such liquid crystal display has motion blur which makes moving pictures look not sharp but fuzzy due to the maintenance characteristics of liquid crystal.
Motion blur is caused by an image integration effect which temporarily lasts as the human eye follows moving objects. To reduce motion blur, moving picture response time (MPRT) needs to be shortened. As one of the methods for shortening the MPRT, a driving frequency variation technology is known. The driving frequency variation technology varies frame frequency, i.e., the number of frames per second, according to changes in images. In the driving frequency variation technology, changes in motion on images IMG1 to IMG4 are detected as shown in FIG. 1, and when the changes in motion on the images are less than a preset value, the images are displayed at a first frame frequency, and when the changes in motion on the images are equal to or greater than the preset value, the images are displayed at a second frame frequency which is higher the first frame frequency.
Increasing frame frequency for an image with a substantial motion change offers better motion blur reduction. However, even if frame frequency is increased for an image with quite a large motion change, it makes little difference in the level of motion blur perceived by the viewer. Increasing frame frequency also increases power consumption. In the related art driving frequency variation technology, frame frequency is unconditionally increased even for a high-speed moving image on which the viewer sees no difference in motion blur. Accordingly, the related art driving frequency variation technology is not disadvantageous in terms of power consumption.